Part of the Gulf Coast barrier islands, Don Pedro lies near the more popular Gasparilla Island. Eleven nature trails weave past giant leather ferns on 225 acres, where you can fish off the dock for flounder, snook, and trout.

Off the northeast coast of Antigua, this spot is known for—you guessed it—abundant exotic bird populations, including red-billed tropicbirds, and the West Indian whistling duck. While burying your toes in the sugary sand, look for other unique wildlife such as the (harmless!) Antiguan racer snake.

How to get there: Travel by private boat, or take a day sail from Antigua with a Tropical Adventures.

Be sure to: Snorkel from the soft sandbar and explore the surrounding coral reef.

Santa Barbara Island

Southwest of Los Angeles, Santa Barbara Island is the smallest of five islands in the Channel Islands National Park, known as North American Galápagos and home to more than 150 unique species. At Landing Cove, you can kayak, snorkel, and swim with garibaldi, the neon orange state fish. Note: SBI has dramatic cliffs, but no beaches.

How to get there: Take a private boat, or charter one through Truth Aquatics.

Be sure to: Check out the Sea Lion Rookery overlook to see the barking behemoths sun themselves on the rocks and swim through kelp-filled-waters.

Long Island, Apostle Islands

The 21 Apostle Islands in Lake Superior are an adventure-seeker's playground. Kayakers, hikers, boaters, divers, and lighthouse enthusiasts—there are six lightstations among the isles—will find plenty to see and do here. Long Island, located in the southeast corner, is one of the more remote spots, with three historic lights (one working) and submerged shipwreck treasures.

Be sure to: Suit up in your scuba gear and spend hours exploring the still-intact hull of the sunken 1886 schooner Lucerne.

Big Talbot Island State Park

Trails lead hikers through marshland and maritime forest to the beach on Big Talbot, located just northeast of Jacksonville. Fishing and guided paddle tours are available with advance reservations; don't forget to pack a lunch to enjoy in the beachfront pavilions.

How to get there: Drive 20 miles east of downtown Jacksonville on A1A North. For guided paddle tours, contact Kayak Amelia. For more info visit floridastateparks.org.

Part of the San Juan Islands, Yellow Island is known for its wildflower-covered landscape. More than 50 species—including the only cactus native to western Washington—can be found here. Check the trees for bald eagles, listen for songbirds, and watch playful otters swim.

How to get there: Take a private boat from San Juan Island's Friday Harbor or Fisherman's Bay on Lopez Island; you can also kayak from Deer Harbor on Orcas Island. For more info visit nature.org.

Be sure to: Scan the shore for black oystercatcher birds prying open mollusks with their vibrant orange-red bills.

West Snake Caye

Seventeen miles from the town of Punta Gorda, the four small Snake cayes lie in the 160-mile Port of Honduras Marine Reserve All the islands, such as West Snake Caye, boat lush mangrove trees and endangered species including the West Indian manatee.

Be sure to: Trek through towering mangroves toward the center of the island, where you'll find a small, serene lagoon.

Isla Espíritu Santo

This large island off Baja California is one of the most biologically diverse places in the world. Certain animals—including the black-tailed jackrabbit—can only be found here. Thirty-one marine animal species, such as sea lions and coral, inhabit the waters.